Overview
The Instrument Transformers Inc 350-801 is a fixed-ratio current transformer (CT) engineered for accurate current measurement and relay protection in three-phase and single-phase power systems. With an 800:5 turns ratio and rated for 600V primary voltage with 10 kV BIL (Basic Insulation Level), this transformer is ideal for metering installations and protection schemes across industrial and utility applications operating at 50–400 Hz.
Key Features
- 800:5 Ampere turns ratio reduces high primary currents to standard 5A secondary for meters and relays
- RF 1.33 rating factor accommodates thermal margin and allows continuous operation under rated conditions
- 10 kV BIL insulation class provides robust protection against voltage transients
- Frequency range 50–400 Hz supports global industrial and utility standards
- Compact window-type design suitable for retrofit and new installations
- Metering accuracy class 0.3 B designation for precise energy measurement
Technical Specifications
| Primary Turns Ratio | 800:5 Amperes |
| Primary Voltage | 600V |
| Secondary Current | 5 Amperes |
| Insulation Level (BIL) | 10 kV |
| Rating Factor (RF) | 1.33 |
| Accuracy Class | 0.3 (Metering) |
| Frequency Range | 50–400 Hz |
| Construction Type | Window-type / Donut |
| Installation Environment | Indoor |
| Series / Model | 350 (OEM ITI Reference) |
Typical Applications
- Revenue metering of 3-phase industrial power feeds and large single-phase loads
- Feeder and transformer protection relay circuits requiring 0.3 metering class accuracy
- Power factor correction and harmonic monitoring systems
- Substation instrument panels and switchgear installations
- Building management systems and energy management platforms requiring precise amp data
Compatibility & Replacements
Compatible With
- Class 0.3 metering relays and digital power meters
- ANSI/IEC standard meter and relay secondaries rated for 5A inputs
- 600V three-phase and single-phase power distribution systems
- Control circuits and protection schemes operating at 50–400 Hz
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. While the 350-801 shares the same 800:5 ratio with certain GE/ITI and Cutler-Hammer current transformers of the same era, direct mechanical and electrical interchangeability must be confirmed by part number cross-reference and mounting verification.
Works With
- ABB, GE, Siemens, and Schneider Electric metering and protection relay platforms
- Power System Stabilizer (PSS) and SCADA systems with 5A secondary inputs
- Handheld clamp-meters and power quality analyzers requiring external CTs
- Legacy and modern distributed energy resource (DER) and microgrid monitoring systems
